SCIENCE PT-3/TERM-2

What causes lightning?

Lightning is caused by charged clouds due to friction from wind.

What was Benjamin Franklin's kite experiment?

Franklin flew a kite during a thunderstorm with metal keys attached to show that lightning is due to charged clouds.

What is an electric charge?

A physical quantity responsible for electrostatic attraction and repulsion between objects.

What are the two types of electric charges?

Positive and Negative.

What happens when two balloons are rubbed with wool?

The balloons repel each other due to similar charges.

What is the process by which an electrically neutral object can be charged by friction?

Friction causes displacement of charges from one object to another.

What is the role of conductors in electric charge transfer?

Conductors allow charges to pass through, enabling the transfer of electricity.

What is the purpose of an electroscope?

An electroscope detects the presence and magnitude of electric charge.

What happens to the leaves of an electroscope when a charged object is brought near?

The leaves may either attract or repel depending on the charge.

What is the phenomenon of electrolysis?

Electrolysis is the decomposition of a substance by passing electricity through it.

What defines a good conductor of electricity?

A substance that allows electric current to flow through easily.

What is the chemical reaction for electrolysis of water?

2H2O -> 2H2 + O2.

What is the function of vacuoles in plant cells?

Vacuoles are used for storage of food and substances in plant cells.

What is the significance of the nucleus in a cell?

The nucleus controls all living functions of a cell and contains the genetic material.

What is myopia?

Myopia, or short-sightedness, is a vision defect where one cannot see far-off objects clearly.

What is the definition of pressure?

Pressure is the result of force applied over an area.

What is atmospheric pressure?

Pressure exerted by the weight of air above a given point.

What is the purpose of a periscope?

To allow a person to see over or around obstacles.

What is the difference between metals and non-metals?

Metals are usually hard, shiny, and good conductors of heat and electricity, while non-metals are dull, soft, and poor conductors.

Which metal is the best conductor of electricity?

Silver.

What is corrosion?

The chemical reaction that leads to the deterioration of metals when exposed to moisture and oxygen.

What is an alloy?

An alloy is a mixture of two or more metals or a metal and non-metal to enhance properties.